Return mechanism for key couplers



March 2, 1954 w, LEEDS 2,670,899

RETURN MECHANISM FOR KEY COUPLERS OF CASH REGISTERS Filed Nov. 13, 1951 INVENTOR. K yle W Leeds. BY

ATTORNEY Patented Mar. 2, 1954 RETURN MECHANISM FOR KEY COUPLER-S OF CASH REGISTERS Kyle W. Leeds, Kansas City, Mo. Application November 13, 1951, Serial No. 256,074

2 Claims.

This invention relates to mechanical cash registers and is more particularly concerned with means for controlling the operation of the key coupler associated with the operating mechanism of these devices.

In mechanical cash registers, the key coupler is a rocker bar which is actuated from the normal position by the downward movement of any one of the keys of the cash register and which, in returning to the normal position under the influence of gravity, with or without the assistance of auxiliary springs, exerts a camming action on levers connected to the keys for returning the keys to their home positions. In ordinary cash registers, this returning action is notoriously abrupt, noisy and results in excessive wear between sliding parts and does not always give a positive restoration for the next operation.

One of the objects of this invention is the provision of means for controlling the return of the keys to their home positions in a smooth operating manner, without undue noise and wear.

Another object is the provision of such means which results in an easier operation, less abruptness in coming to rest and positive restoration for the next operation.

A further object is the provision of such means in combination with the key coupler of a cash register comprising an extension arm secured to the coupler and a floating lever pivoted to the frame of the register, the arm being connected to the lever by a tensioned spring on one side of the pivot point, another anchor spring being provided between the lever on the other side of the pivot point and the frame of the machine.

These and other objects and advantages of the invention will be apparent from the following description considered together with the accompanying drawing, in which:

The figure of the drawing is a schematic side elevational view of a typical cash register showing the elements of my invention thereon and their relation to the ordinary key coupler thereof.

Referring with more particularity to the drawing in which like numerals designate like parts, the embodiment illustrated is in conjunction with the ordinary key coupler ll of a cash register, designated generally by the numeral I2. The key coupler is rocked on a horizontal shaft 13 to which it is eccentrically pivoted and an extension arm is secured to one side of the coupler, such as by screws or bolts [4a. Said arm l4 projects through an aperture l5 of the side frame plate 16. The outer end of the arm is connected to one end of a tensioned coil spring H. The other end of said coil spring is connected to the longer arm l8 of a horizontal floating bar or lever l9. Said lever I9 is pivoted on a stub shaft 20 of the side frame plate 16, below the arm [4. One end of another tensioned coil spring 2| is connected to the shorter arm 22 of the bar IS. The other end of said coil spring 2| is anchored at an upper point, such as the post 23 on the frame plate l6.

By these means, as the key coupler moves upward from the normal position shown in the drawing, it is biased by the differential action of the springs l7 and 2| combined with the differential action of the unequal arms of the floating lever, resulting in a subsequent smooth return to the normal position.

In actual operation, it is found that, using relatively weak springs of substantially equal tension, instead of a single heavy spring as ordinarily used, optimum results are obtained if the shorter arm 22 represents two-fifths of the total weight of the lever 19 and the longer arm l8, threefifths of said total weight.

The smooth return movement is achieved with this arrangement because tension and stretch between the two springs are always proportioned by the floating bar. Since the tension in these springs are additive and the displacement subtractive, the necessary force to operate the coupler is furnished by only a small differential movement, thereby giving a smooth and quiet operation.

Having thus described my invention, I claim:

1. In a cash register having a frame and a key coupler pivoted relative to the frame, an extension arm secured to said coupler, a horizontal floating lever pivoted relative to the frame, said lever having a long arm and a short arm, a tensioned coil spring having one end connected to said extension arm and the other end to the long arm of the said lever, a second coil spring having one of its ends connected to the shorter arm of said lever and its other end anchored to said frame in opposition to the action of said first mentioned spring.

2. In a cash register having a frame and a key coupler pivoted relative to the frame, an extension arm secured to said coupler, a horizontal floating lever pivoted relative to the frame, said lever having a long arm and a short arm, a tensioned coil spring having one end connected to said extension arm and the other end to the long arm of the said lever, a second coil spring having one of its ends connected to the shorter arm of said lever and its other end anchored to said frame in opposition to the action of said first mentioned spring, the lengths of said longer and shorter arms being three-fifths and twofifths, respectively, of the total length of the lever.

KYLE W. LEEDS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 860,602 Hopkins July 16, 1907 1,556,756 Camp Oct. 13, 1925 1,874,285 Green Aug. 30, 1932 

